Providing only simple locks, such as padlocks or combination locks, on cargo containers is often ineffective at deterring thieves. The thief may use a crowbar, blowtorch, bolt cutter, or any number of other means to break the lock and then access the contents of the container. Thus, devices have been proposed to protect the lock from being surreptitiously removed. For example, Bunger, Padlock Protector, U.S. Pat. No. 5,261,258 (Nov. 16, 1993) shows a padlock disposed within a housing that closely fits around the lock. Another patent to Bunger, Padlock Protector, U.S. Pat. No. 6,367,292 (Apr. 9, 2002) shows the closely fitting casing disposed within a housing. Eberly, Padlock Protector, U.S. Pat. No. 4,898,008 (Feb. 6, 1990) shows a housing that encloses a portion of the shackle of the padlock.
However, all of the devices described above are potentially vulnerable to drills, blow-torches, or to freezing devices since the lock actuator (key, tumbler, or other mechanism), the lock, or the area near the lock can still be easily reached. Thus, more secure devices are needed to protect locks, especially on containers that may be left unattended for extended periods of time.